Module 4.2 Flashcards
Diode
A component that allows current through in one direction only. In the
correct direction, diodes have a threshold voltage (typically 0.6 V) above which
current can flow
Electromotive Force
The energy supplied by a source per unit charge passing
through the source, measured in volts.
Filament Lamp
A bulb consisting of a metal filament, that heats up and glows to
produce light. As the filament increases in temperature, its resistance increases
since the metal ions vibrate more and make it harder for the charge carriers to
pass through
I-V Characteristics
Plots of current against voltage, that show how different
components behave
Kilowatt-Hour
A unit of electrical energy. It is usually used to measure domestic
power consumption.
Light-Dependent Resistor
A light sensitive semiconductor whose resistance
increases when light intensity decreases
Ohm
The unit of resistance
Ohmic Conductor
A conductor for which the current flow is directly proportional
to the potential difference across it, when under constant physical conditions
Ohm’s Law
The current and potential difference through an ohmic conductor
held under constant physical conditions are directly proportional, with the constant
of proportionality being resistance.
Potential Difference
The difference in electrical potential between two points in a
circuit. It is also the work done per coulomb to move a charge from the lower
potential point to the higher potential point. It is measured in Volts
Power
The rate of energy transfer in a circuit. It can be calculated as the product
of the current and the potential difference between two points. It is measured in
Watts
Resistance
A measure of how difficult it is for current to flow through a material.
Resistivity
A measure of how difficult it is for charge to travel through a material.
It is proportional to the object’s resistance and cross-sectional area, and inversely
proportional to the object’s length. It is measured in Ohm metres.
Resistor
A device that has a fixed resistance and follows Ohm’s law
Volt
The unit of potential difference
What is a electron gun
An electron gun is a device used to produce a thin beam of electrons, which are accelerated to
high speeds. A small metal filament, which acts as a cathode, is heated by passing a potential
difference through it. Some of the electrons in the metal gain enough kinetic energy to escape the
metal, in a process known as thermionic emission
what equation likes the charge of an electron, accelerating potential difference/the potential difference between the filament and the anode, and kinetic energy
eV = 1/2 mv^2
NCT thermistor
This means as the temperature of the material increases, the resistance of
the material decreases. The change in resistance is usually dramatic, so
they are useful in temperature sensing circuits such as thermometers and
thermostats
